Small glass beads, or microspheres, have traditionally been used in a variety of applications. In one widely-used application, the microspheres are added to any of a variety of polymer compositions, with these compositions benefiting from the inclusion of the beads in any of a number of ways. For example, they may be used as reinforcement fillers for both thermoplastics and thermosetting resins to improve physical and thermal properties, reduce cost, and solve production problems. The spherical shape and non-porous morphology provides certain advantages when used in such applications. Incorporation of spherical glass particles increases the flow rate of polymers during forming operations, much as though the spheres are acting as tiny ball bearings. The non-porous and isotropic qualities of the microspheres may allow use of higher filler loadings, thereby reducing cost, and may further minimize the viscous drag between particles and allow for uniform and controllable shrinkage of molded parts during the cooling cycle. Typically, this helps to achieve formation of a smooth surface finish on the resulting parts.
Other particulate fillers, such as calcium carbonate, talc, and titanium dioxide may be used in polymer composites, coatings, and other formulation where whitening of the finished product is desired. However, many such fillers have irregular shapes and high surface areas that result in impeded flow during molding or other forming operations, thereby making such forming operations more difficult. It would be desirable to be able to use fillers that whiten compositions containing them, and provide the advantages afforded by spherical particles.